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Resistors have different wattage?

Last response: in Graphics & Displays
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June 27, 2006 7:15:05 PM

At this link: http://www.vr-zone.com/index.php?i=3330&s=2
It isn't too clear on the bottom method of the page whether or not I have to work my way up each step up to step 3 to get 1.6v or do i just jump to step 3 to get 1.6v? If anyone has done this mod, please tell me what I should do.
One more thing. On step 1 it says to replace with 50k ohms resistor but it does not tell me what type of wattage 50k ohms resistor I need. Can anybody tell me? 8O

More about : resistors wattage

June 27, 2006 11:19:18 PM

Did you try contacting VR-Zone directly or asking them in their forums?
June 27, 2006 11:56:36 PM

good idea :p 
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June 28, 2006 12:19:20 AM

If you're replace it with the same size, it will be the
same wattage.
June 28, 2006 12:37:37 AM

For 1.6volts you need to go step by step thats why they are called steps. that over current protect is most likely not needed though i would not do it.
anyways it wont hurt if you do all three as long as you set at maximum resistance of 50K on the vr before you do the 1.6v mod. I have not done this mod but have done many others 800gto2,7900gtx p5wd2-e i would never disable a overcurrent protect circuit. I would change the value of the resistors before i removed them

2nd wattage is not important really because current is low. any basic 50k VR will do.
the 0402 size resitors are normally 1/16 watt to give you an idea but they can go up to 1 watt. you cant tell by looking at them though.
June 28, 2006 4:58:30 AM

I don't know who to believe! Here is a reply I got to the same question from vr-zone:

is either u do step 1 OR step 2, OR step 3, step 1 is troublesome in removing the SMD resistors.
for values 10k and above for modding gpus, 1/8w or 1/4w resistors will do just fine

I can get 1.6v without removing the overcurrent protect circuit? I'll take your word for it since you have done the same mod to a gtx.
Thanks IcBIUsCrn! :o 
June 30, 2006 1:37:18 PM

As far as the mods are concerned:
step 1 for 1.5 volts
steps 1, 2, 3 for 1.6 volts
steps 1, 2, 4 for 1.7 volts

As far as resistor wattage is concerned, the resistance values are so high that currents are very low, thus 1/16 watt resistors would work.
However, just soldering a variable resistor across a fixed resistor can be dangerous. Simply put, if you adjust the variable resistor to zero or anything close to it, the total resistance will go to zero (that is it will short circuit). The preferred method would be to put a small resistor in series with the variable resistor to limit the resulting voltage to a reasonable value.
June 30, 2006 2:13:05 PM

Quote:
At this link: http://www.vr-zone.com/index.php?i=3330&s=2
It isn't too clear on the bottom method of the page whether or not I have to work my way up each step up to step 3 to get 1.6v or do i just jump to step 3 to get 1.6v? If anyone has done this mod, please tell me what I should do.
One more thing. On step 1 it says to replace with 50k ohms resistor but it does not tell me what type of wattage 50k ohms resistor I need. Can anybody tell me? 8O

when buying a resistor there are two thing you have to look at: resistance and wattage. The voltage does not matter, as it will be given by the circuit design and other stuff.

to calculate wattage use this formula:

P=R x I^2

or this:

P=V x I

P=wattage
R=resistance
I=current in amperes
V=voltage
June 30, 2006 2:47:39 PM

The power rating of the resistor should be labeled somewhere on the resistor if its larger, or ont he packaging for small surface mounts. Larger power resistors are used when theres a lot of current, if you're replacing a surface mounted resistor theres a good chance its 1/4W or 1/8W liek they said. Besides, if you tried to stick a big power resistor in its place im not sure it would fit even.
June 30, 2006 2:49:25 PM

It might be tough to guess the current if you don't know the voltage... which we don't. A safe guess might be V = 12V, from the power supply rails. That could then be used in the power calculation P = V*V / R, which means 144 / (something) watts. As long as R is greater than 576 Ohms, you can use a 1/4 watt resistor. Greater than 1152 Ohms (e.g. 1.2K), and you can use 1/8 watt. You get the idea.

<b>Note:</b>This assumes the power supply rails aren't stepped up to a higher voltage. I don't believe they are, but that's worth determining before you proceed with a decision.

Also, I second the idea of adding a small resistor (e.g. the 1.2K, 1/8 watt) in series with the variable resistor, so that if you do accidentally rotate the thing to 0, you'll still have some resistance.
June 30, 2006 2:54:17 PM

Quote:
It might be tough to guess the current if you don't know the voltage... which we don't. A safe guess might be V = 12V, from the power supply rails. That could then be used in the power calculation P = V*V / R, which means 144 / (something) watts. As long as R is greater than 576 Ohms, you can use a 1/4 watt resistor. Greater than 1152 Ohms (e.g. 1.2K), and you can use 1/8 watt. You get the idea.

<b>Note:</b>This assumes the power supply rails aren't stepped up to a higher voltage. I don't believe they are, but that's worth determining before you proceed with a decision.

Also, I second the idea of adding a small resistor (e.g. the 1.2K, 1/8 watt) in series with the variable resistor, so that if you do accidentally rotate the thing to 0, you'll still have some resistance.

he can measure the voltage with the default resistor. That would be the "default" voltage. Then use the formula to calculate teh current and the resistance.
If the guy is gonna do a v-mod i suppose he has at least a precision multimeter.......
June 30, 2006 4:02:14 PM

Ok, I'm going to attempt steps 1 and 3. I'll just ignore step 2 as IcBIUsCrn tells me. I'll make sure to get the 0402 1/16 watt resistor as well. I have to go to Las Cruces for the weekend but when i'm back i'll keep all of you updated on the outcome of this. Thank you for your help Anoobis, tmac, IcBIUsCrn, djpont, jap0nes, Vash-HT, and TeraMedia. If I fail, there's always suicide :o 
June 30, 2006 6:22:06 PM

Quote:
Ok, I'm going to attempt steps 1 and 3. I'll just ignore step 2 as IcBIUsCrn tells me. I'll make sure to get the 0402 1/16 watt resistor as well. I have to go to Las Cruces for the weekend but when i'm back i'll keep all of you updated on the outcome of this. Thank you for your help Anoobis, tmac, IcBIUsCrn, djpont, jap0nes, Vash-HT, and TeraMedia. If I fail, there's always suicide :o 


Why do you need to get 0402 resistors? all you need is a 50k variable resistor, you do need 0402 resistors if you plan on changing the 2, 10k ohms resistors in step 2 for a higher value if needed also it won hurt if you go with a higher watt rating then needed.

what yantronic was saying in the other forum ocp is Over Current Protect mod is not needed unless you have problems shutting down on you.

by the way you do have proper cooling right?
July 3, 2006 8:14:32 AM

Yeah, I have enough cooling for this mod. If it won't hurt I should perform step 2 as well. What kind of resistors should I replace the ones in step 2 with?
This seems to be a nice place to buy from: http://www.web-tronics.com/recmulcersea.html

Thanks again for your trouble IcBIUsCrn. :) 
March 30, 2010 5:53:10 PM

hi,

I am looking for a bigger wattage resistor unfortunately its difficult to find it here. Is there a way that i can increase wattage by adding another resistor? Please advice.


Thanks,
Mabster
March 30, 2010 6:42:41 PM

I sell resistors everyday

you need value, wattage, tolerance, temperture coeffecnt, package type.

You can piggy back resitors of the same type to double wattage of said resistors I think.
!